1. Field of the Invention
This invention relates to a process for preparing an elaborate anti-corrosive and protective coating of a metal such as titanium bonded tightly on the surface of a substrate such as metals, metal oxides and plastics according to the electrodeposition method using low pressure steam or inert gas as an electrodeposition atmosphere.
2. Description of the Prior Art
Protective coatings of metals, especially titanium, are industrially very useful because they are ductile and are excellent in the corrosion resistance and heat resistance. However, it has heretofore been impossible to prepare coatings of metals such as titanium on an industrial scale by chemical or electrochemical plating methods.
As the physical means for forming metal coatings, there can be mentioned a vacuum evaporation coating method. According to this method, it is possible to form a very thin filmy coating, but the resulting coating is very poor in adherence to the substrate and it is readily wiped away by fingers. According to the sputtering method, which is included in the category of the vacuum evaporation coating method, it is possible to obtain a metal coating having an improved adherence to the substrate, but the coating is so weak that it cannot be used as a protective coating. Further, since the evaporation deposition rate is very low in this sputtering method, this method is of no industrial utility when it is desired to obtain coatings of a sufficient thickness.